Japanese Patent Application Laid-open No. 2003-128235 discloses a conveying apparatus for transferring articles. A large number of article support bodies oriented in the direction perpendicular to a main conveying path are attached between a pair of left and right endless rotary bodies installed along the main conveying path, a guided body is provided at the rear surface side of article sidewise push bodies that are guided by the article support bodies, and a guide device is provided for guiding the guided body. The endless rotary bodies are of an endless chain system and special linking pins are provided inwardly at the endless rotary bodies. Side members are provided at both ends of the article support bodies and the special linking pins are inserted into and joined with tubular linking sections formed in the side members, whereby both ends of the article support bodies are linked to the endless chain via the respective side members. Furthermore, a mating section that can be externally fitted onto the linking section of the adjacent side member is formed at the other end of the side member.
The linking portions located between the side members are configured by taking into account assemblability and maintainability and also so that they can extend or contract with respect to each other and bend with respect to each other in a reversal section at the start and finish ends of the main conveying path. Thus, a large-diameter portion is formed in the tubular linking section and the mating section is formed as a recess that is open on both, inner and outer, sides and outwardly on the other side. As a result, the circumferential surface of the large-diameter portion is mated with a pair of parallel mating surfaces in the mating section in a state of point contact (linear contact in the left-right direction) in the side view thereof.
However, with the above-described conventional configuration, the article support bodies are linked to the endless chain by inserting the special linking pins and joining them to linking sections of the side member, and such a joint state is difficult to maintain. Thus, for example, when the article support body or endless chain vibrates in the lateral direction and a pull-out force acts at the insertion and joining section, the endless chain withdraws from the article support body and the joint state is disrupted. As a result, the endless chain cannot rotate smoothly, and there is a risk of noise generation by the play or separation from the sprockets.
Furthermore, in the portion where the circumferential surface is in point contact (linear contact) with a flat mating surface, a gap is necessary to provide for smooth extension-contraction or bending in the reversal section. Due to such a gap in the point contact portion, noise is generated by play in the reversal section. Furthermore, the portions of the circumferential surface that are in point contact are easily worn out by repeated extension-shrinkage movement or bending movement, thereby enlarging the gap and increasing the noise produced by play.
Yet another conventional configuration of a conveying apparatus is described in Japanese Patent Application Laid-open No. 6-115680. In this configuration, the linking shaft that links the links in a chain has a large protrusion length. A mounting member is attached to the end surface of a slat, and the linking shaft of the chain is inserted and fixed in a tubular section formed in the plate section of the mounting members. As a result, a large number of slats are attached between a pair of left and right chains, and shoes are provided that are externally fitted on the slats and guided thereby. In a shoe, a face surface section, a rear surface section, and a front surface section are formed integrally, and mounting surface sections with a rear side inclined inwardly are formed at an inclination angle of 30 degrees at both sides of the rear portion of the face surface section. Buffer members made from a urethane resin are detachably attached to the mounting surface sections.
However, with the above-described other conventional configuration, the slats are linked to the chain by inserting and fixing the linking shaft in the tubular section of the mounting member, and such a joint state is difficult to maintain. Thus, for example, when the slat or chain vibrates in the lateral direction and a pull-out force acts at the insertion and fixing section, the chain withdraws from the slat and the joint state is disrupted. As a result, the chain cannot rotate smoothly, and there is a risk of noise generation by the play or separation from sprockets.
Further, because the buffer member is attached only to both sides of the rear portion of the face surface section of the shoe, a gap appears between the rear end of the buffer member provided at a shoe positioned in front and a front end of the buffer member provided at the shoe positioned behind. As a result, in particular, in the case of small articles, the pushing surfaces of the buffer members abut against the eccentric positions (eccentric locations) and the distribution of the articles cannot be performed with good stability. To resolve this problem, a shoe can be increased in size to decrease the front-rear spacing of the shoes (the front-rear gap), but when the shoes themselves are increased in size, there is a risk of clasping an article between the rearmost shoe that advances forward at a side and a front most shoe that is distributed and moves sidewise.